Both empirical and modeling studies support the notion that sexual network structure plays a central role in transmission dynamics of sexually transmitted infections (STIs) such as human immunodeficiency virus type 1 (HIV-1). Among men who have sex with men (MSM), venues such as bars and clubs can not only shape these sexual networks, but also shape networks of illicit drug use, especially of so-called `club drugs'. As the use of `club drugs', especially methamphetamine, has been associated with increased levels of HIV risk behaviors, it is important to understand the intersection of club drug use and sexual networks among MSM. This proposal seeks to develop models to tease apart individual- versus venue-level factors in HIV risk behaviors, illicit drug use, and their interaction. Firstly, we will adapt statistical models previously used to study the impact of neighborhood effects on health to the scale of individual bars and clubs in order to describe the spatial distribution of illicit drug use and HIV risk behaviors. These models will be applied to pilot data from a time-location sampling study of non-injection drug use and HIV risk behaviors among men who have sex with men. Secondly, we will develop a dynamic venue-based network model of HIV risk behavior and drug use. These models will allow us to assess the role that venues play in structuring HIV risk and drug use networks, and the possible impact of behavioral interventions targeted at risk behaviors and drug use at the environmental level. This proposal will help the Principal Investigator transition to being an independent researcher in the area of HIV and drug use, while exploiting his current skill set. [unreadable] [unreadable] PUBLIC HEALTH RELEVANCE: Among men who have sex with men (MSM), venues such as bars and clubs can shape both sexual networks and networks of illicit drug use, especially of so-called `club drugs'. We will use statistical models to describe the spatial distribution of illicit drug use and HIV risk behaviors, and develop a dynamic venue-based network model of HIV risk behavior and drug use, which will be parameterized using social network based methods. These models will allow us to assess the role that venues play in structuring HIV risk and drug use networks, and the possible impact of behavioral interventions targeted at risk behaviors and drug use at the environmental level. [unreadable] [unreadable] [unreadable]